The present invention pertains to a bicycle safety light. More particularly, the present invention pertains to a bicycle safety light that is mounted on the spokes of a bicycle tire, and produces a flashing light to increase the visibility of the bicycle when riding at night.
Bicycles are a well known device, and unfortunately, so are the issues of safety associated with their use. The present invention has been developed to address and solve one of the most pressing safety concerns a cyclist has when riding at night. Namely, the lack of visibility of the bicyclist by others, such as motorists. It is well known to provide some degree of added visibility through the addition of reflective surfaces supported by the spokes and/or frame of the bicycle. With these reflecting devices, an external light source such as an oncoming car light, impinges on the reflective surface, and is reflected back to the source (i.e. the cat's driver). These devices are particularly useful when mounted on the spokes of the bicycle. As the bicyclist moves forward, the bicycle's wheels continuously rotate, and thus the reflective devices mounted on the spokes undergo a cycloid movement pattern. The light reflected by the reflective device while moving in this pattern catches the eye of the viewer, thus drawing attention to the cyclist.
It is also well known to dispose a light source, such as a head or tail light to the bicycle at a stationary position, such as in front of the handlebars or behind the seat. Since the light source does not require the external light beam (as the reflective device does), the cyclist can be seen even if the viewer's line of sight is not in line with the external light source (i.e. the head light). However, the stationary mounting at the head of the handlebars or back of seat, is ineffective for producing the better suited cycloid pattern described above. Also, with this orientation of the light source, the light beam is not directed toward the side of the bicycle, and this does not provide adequate side visibility.
A light may be fixed to the spokes of a bicycle. However, such a light would have to be thin enough to pass between the forks supporting the rotating tire, durable enough to sustain extremely hard bumps, and bright enough to be highly visible. In addition, such a light should preferably flash on and off, to be more visually stimulating, and thus more likely to be perceived by a viewer at night.
However, it is difficult to provide such a light source due to a number of practical concerns. For example, the external surfaces of such a bicycle safety light would be constantly exposed to extremes of moisture, temperature, rain, dirt, shocks, and vibrations. Therefore, the housing of such a safety light must be adequately sealed to protect the internal light producing components from the elements. One way to provide integrity for the housing of the safety light would be to hermetically seal it at the factory. However, in this case it would be impossible to replace any internal components, such as a power source, light sources, etc. Therefore, if the power source is a battery, once the factory installed battery has become discharged, the safety light would be ineffective for its intended use since, to replace the battery one would have to break the factory created hermetic seal.
A light source supported on the spokes of a tire is useful, only so long as it is turned on. Therefore, a switch would be needed to alternately supply and disconnect power from a power source. However, the bicyclist, particularly a young child, is apt to forget to flip the switch and turn the light source on. Also, if the light source is powered by, for example, a battery, if the bicyclist forgets to flip the switch off, the battery will drain, making the device useless until such time as the battery is replaced.
There have been prior attempts at providing a safety light for a bicycle which provides a light source mounted on the spokes of the bicycle tire. U.S. Pat. No. 4,176,390, issued to Galbert, discloses a light in which a switch spring is provided for biasing a battery normally out of electrical contact with a bulb when the tire is not rotating. When the tire is rotating, centrifugal force urges the battery against the spring so that the light is turned on. However, this attempt fails to provide the desired flashing light. Also, since the light is constantly on while the tire is rotating, and the bulb is a conventional incandescent light bulb, the battery will tend to drain rather quickly, making the device useless until a fresh battery is installed. Furthermore, as soon as the tire stops rotating (for example, when the bicyclist comes to a road intersection), or if the centrifugal force is slight (such as when walking the bicycle or riding slowly), the light is turned off, making the bicyclist substantially invisible to night traffic.
Another prior attempt, U.S. Pat. No. 4,135,229, issued to Modurkay, teaches a light bulb fixed to a plate supported by the spokes of a bicycle tire. A relatively bulky battery power source is clamped to the tire's hub. The bulb and the battery are connected through a wire. This attempt also provides a constant light source when its switch is turned on, and if the switch is not turned off, the device's incandescent light bulb will quickly drain the battery of power.
In another prior attempt, U.S. Pat. No. 4,787,014, issued to Wodder et al., another safety light is provided. In this attempt, a constant light source is secured to a thin plate supported on the spokes of a bicycle tire. As with Galbert, the light is oriented so that its beam shines toward the rim of the tire (along it longitudinal axis). This orientation appears to be a requirement of these devices, since the light source and battery are relatively long. However, with this orientation. the light source directs a thin beam that will often not be seen unless the viewer is directly in front or behind the cyclist. Stated otherwise, this orientation does not present a light beam directed towards the sides of the bicycle (or perpendicular to the longitudinal axis of the tire). Wodder et al. recognizes that the orientation disclosed in this reference directs a light beam which is obscured by the tire rim. To alleviate this problem, Wodder et al. discloses that a wedge or lip can be used to elevate the light source so a portion of the light beam can be deflected away from the tire rim. However, even with this feature, the light beam is at most elevated only 20 degrees from the tire's longitudinal axis. This orientation still does not provide adequate side visibility.
In another attempt, UK Patent 2,237,368, issued to Wayte, a flashing lamp is provided with a gravity-operated change-over switch. The switch is activated by motion to alternately charge a capacitor from a battery, and then discharge the capacitor through the lamp. In accordance with this reference, the lamp flashes once per wheel revolution. However, the simple circuit construction causes the lamp to stop flashing as soon as the tire stops rotating. Thus, as with the other prior attempts, if the bicyclist momentarily stops, such as at an intersection, there is no light produced and the bicyclist again becomes invisible to night traffic.
The requirement of a battery power source makes these prior attempts less than adequate, since once the battery's power has been drained, no light is produced until a fresh battery is installed. There have been attempts to provide a self-generating power source which uses the tire's rotating motion to drive an electric generator. Examples of prior attempts are: U.S. Pat. No. 4,796,972, issued to Thomas et al.; U.S. Pat. No. 4,191,988, issued to Kumakura; Canadian Patent No. 888928, issued to Choquette et al.; UK Patent No. 2168660, issued to Roberts; and Japanese Patent No. 52-25597, issued to Kaneko. These references. generally, utilize the rotation of the bicycle tire to drive an electric generator. In most cases, the generator consists of a rotationally driven member which is frictionally driven by the bicycle tire. The rotationally driven member causes a permanent magnet to rotate relative to a wire coil so that electricity can be generated. These attempts disclose devices that are relatively expensive, and in most cases add additional bulk and excessive drag on the bicycle.